From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Jim Mattson <jmattson@google.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
Oliver Upton <oupton@google.com>, Peter Shier <pshier@google.com>
Subject: [PATCH v5 15/27] KVM: x86: Formalize blocking of nested pending exceptions
Date: Tue, 30 Aug 2022 23:16:02 +0000 [thread overview]
Message-ID: <20220830231614.3580124-16-seanjc@google.com> (raw)
In-Reply-To: <20220830231614.3580124-1-seanjc@google.com>
Capture nested_run_pending as block_pending_exceptions so that the logic
of why exceptions are blocked only needs to be documented once instead of
at every place that employs the logic.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/kvm/svm/nested.c | 26 ++++++++++++++++----------
arch/x86/kvm/vmx/nested.c | 29 ++++++++++++++++++-----------
2 files changed, 34 insertions(+), 21 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 8f991592d277..a6111392985c 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1356,10 +1356,22 @@ static inline bool nested_exit_on_init(struct vcpu_svm *svm)
static int svm_check_nested_events(struct kvm_vcpu *vcpu)
{
- struct vcpu_svm *svm = to_svm(vcpu);
- bool block_nested_events =
- kvm_event_needs_reinjection(vcpu) || svm->nested.nested_run_pending;
struct kvm_lapic *apic = vcpu->arch.apic;
+ struct vcpu_svm *svm = to_svm(vcpu);
+ /*
+ * Only a pending nested run blocks a pending exception. If there is a
+ * previously injected event, the pending exception occurred while said
+ * event was being delivered and thus needs to be handled.
+ */
+ bool block_nested_exceptions = svm->nested.nested_run_pending;
+ /*
+ * New events (not exceptions) are only recognized at instruction
+ * boundaries. If an event needs reinjection, then KVM is handling a
+ * VM-Exit that occurred _during_ instruction execution; new events are
+ * blocked until the instruction completes.
+ */
+ bool block_nested_events = block_nested_exceptions ||
+ kvm_event_needs_reinjection(vcpu);
if (lapic_in_kernel(vcpu) &&
test_bit(KVM_APIC_INIT, &apic->pending_events)) {
@@ -1372,13 +1384,7 @@ static int svm_check_nested_events(struct kvm_vcpu *vcpu)
}
if (vcpu->arch.exception.pending) {
- /*
- * Only a pending nested run can block a pending exception.
- * Otherwise an injected NMI/interrupt should either be
- * lost or delivered to the nested hypervisor in the EXITINTINFO
- * vmcb field, while delivering the pending exception.
- */
- if (svm->nested.nested_run_pending)
+ if (block_nested_exceptions)
return -EBUSY;
if (!nested_exit_on_exception(svm))
return 0;
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index cbbe62a84493..4bc2250502ea 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3899,11 +3899,23 @@ static bool nested_vmx_preemption_timer_pending(struct kvm_vcpu *vcpu)
static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
{
- struct vcpu_vmx *vmx = to_vmx(vcpu);
- unsigned long exit_qual;
- bool block_nested_events =
- vmx->nested.nested_run_pending || kvm_event_needs_reinjection(vcpu);
struct kvm_lapic *apic = vcpu->arch.apic;
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ unsigned long exit_qual;
+ /*
+ * Only a pending nested run blocks a pending exception. If there is a
+ * previously injected event, the pending exception occurred while said
+ * event was being delivered and thus needs to be handled.
+ */
+ bool block_nested_exceptions = vmx->nested.nested_run_pending;
+ /*
+ * New events (not exceptions) are only recognized at instruction
+ * boundaries. If an event needs reinjection, then KVM is handling a
+ * VM-Exit that occurred _during_ instruction execution; new events are
+ * blocked until the instruction completes.
+ */
+ bool block_nested_events = block_nested_exceptions ||
+ kvm_event_needs_reinjection(vcpu);
if (lapic_in_kernel(vcpu) &&
test_bit(KVM_APIC_INIT, &apic->pending_events)) {
@@ -3942,15 +3954,10 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
* for TSS T flag #DBs). KVM also doesn't save/restore pending MTF
* across SMI/RSM as it should; that needs to be addressed in order to
* prioritize SMI over MTF and trap-like #DBs.
- *
- * Note that only a pending nested run can block a pending exception.
- * Otherwise an injected NMI/interrupt should either be
- * lost or delivered to the nested hypervisor in the IDT_VECTORING_INFO,
- * while delivering the pending exception.
*/
if (vcpu->arch.exception.pending &&
!(vmx_get_pending_dbg_trap(vcpu) & ~DR6_BT)) {
- if (vmx->nested.nested_run_pending)
+ if (block_nested_exceptions)
return -EBUSY;
if (!nested_vmx_check_exception(vcpu, &exit_qual))
goto no_vmexit;
@@ -3967,7 +3974,7 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
}
if (vcpu->arch.exception.pending) {
- if (vmx->nested.nested_run_pending)
+ if (block_nested_exceptions)
return -EBUSY;
if (!nested_vmx_check_exception(vcpu, &exit_qual))
goto no_vmexit;
--
2.37.2.672.g94769d06f0-goog
next prev parent reply other threads:[~2022-08-30 23:19 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-30 23:15 [PATCH v5 00/27] KVM: x86: Event/exception fixes and cleanups Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 01/27] KVM: nVMX: Unconditionally purge queued/injected events on nested "exit" Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 02/27] KVM: VMX: Drop bits 31:16 when shoving exception error code into VMCS Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 03/27] KVM: x86: Don't check for code breakpoints when emulating on exception Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 04/27] KVM: x86: Allow clearing RFLAGS.RF on forced emulation to test code #DBs Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 05/27] KVM: x86: Suppress code #DBs on Intel if MOV/POP SS blocking is active Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 06/27] KVM: nVMX: Treat General Detect #DB (DR7.GD=1) as fault-like Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 07/27] KVM: nVMX: Prioritize TSS T-flag #DBs over Monitor Trap Flag Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 08/27] KVM: x86: Treat #DBs from the emulator as fault-like (code and DR7.GD=1) Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 09/27] KVM: x86: Use DR7_GD macro instead of open coding check in emulator Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 10/27] KVM: nVMX: Ignore SIPI that arrives in L2 when vCPU is not in WFS Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 11/27] KVM: nVMX: Unconditionally clear mtf_pending on nested VM-Exit Sean Christopherson
2022-08-30 23:15 ` [PATCH v5 12/27] KVM: VMX: Inject #PF on ENCLS as "emulated" #PF Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 13/27] KVM: x86: Rename kvm_x86_ops.queue_exception to inject_exception Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 14/27] KVM: x86: Make kvm_queued_exception a properly named, visible struct Sean Christopherson
2022-08-30 23:16 ` Sean Christopherson [this message]
2022-08-30 23:16 ` [PATCH v5 16/27] KVM: x86: Use kvm_queue_exception_e() to queue #DF Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 17/27] KVM: x86: Hoist nested event checks above event injection logic Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 18/27] KVM: x86: Evaluate ability to inject SMI/NMI/IRQ after potential VM-Exit Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 19/27] KVM: nVMX: Add a helper to identify low-priority #DB traps Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 20/27] KVM: nVMX: Document priority of all known events on Intel CPUs Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 21/27] KVM: x86: Morph pending exceptions to pending VM-Exits at queue time Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 22/27] KVM: x86: Treat pending TRIPLE_FAULT requests as pending exceptions Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 23/27] KVM: VMX: Update MTF and ICEBP comments to document KVM's subtle behavior Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 24/27] KVM: x86: Rename inject_pending_events() to kvm_check_and_inject_events() Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 25/27] KVM: selftests: Use uapi header to get VMX and SVM exit reasons/codes Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 26/27] KVM: selftests: Add an x86-only test to verify nested exception queueing Sean Christopherson
2022-08-30 23:16 ` [PATCH v5 27/27] KVM: x86: Allow force_emulation_prefix to be written without a reload Sean Christopherson
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